Carving method and projector



y 1, 1945- H. L. COOKE CARVING METHOD AND PROJECTOR Filed Sept. 18,1941' 3 Sheets-Sheet l K 5 mm m M m L AY .WB 12% z May 1, 1945. H. L.COOKE CARVING METHOD AND PROJECTOR Filed Sept. 18, 1941 3 Sheets-Sheet 2INVENFR flE/QEWAED A. 0 0/65 ATTORNEYS May -1, 1945. H. COOKE I CARVINGMETHOD AND PROJECTOR 1941 3 Shegts-Sheet 3 Filed Sept l8 INVENTOR vf/s/esu/n an A (oaks mjbayr ATTORNEYS Patented May 1, 1945 OABVINGMETHOD AND PROJECTOR Hereward Lester Cooke, Princeton, N. 1., assignmtoAero Survey Corporation, a corporation of Delaware Application September18, 1941, Serial No. 411,302

11 Claims.

In my United States Patent No. 1,980,981, I have disclosed a method andapparatus for shaping or carving relief models in accordance with withthe optical or plastic image, the block thereupon constituting an exactthree dimensional replica of the terrain shown in the photographs. Incarving the block to correspond with the plastic image, some difllcultyhas been experienced in seeing or identifying the surface of the blockso as to tell when it corresponds with the visible optical image. Theobject of the present invention is to obviate this diiiiculty.

The present invention relates to a method and apparatus for renderingthe surface being shaped or carved clearly visible and identifiable.This is preferably accomplished by projecting spots of light or apattern of bright rays upon the block being carved, which enables itssurface to be identified and the position of the surface to be comparedwith the position of the projected optical or plastic image. The patternof bright rays is preferably caused to vary either in intensity orposition, or both, so as to facilitate the identification of the surfacebeing carved.

In the accompanying drawings 1 have illustrated certain preferred formsof apparatus adapted for the performance of the method of the presentinvention. In these drawings:

Figure 1 is a diagrammatic side elevation, partly in vertical section,showing an apparatus for projecting spots of light upon the body to beshaped or carved.

Figure 2 is a plan view of part of the perforated movable disc throughwhich the light is projected.

Figure 3 is a side elevation of a modified form of projection apparatus,parts being shown in vertical section.

Figure 4 is a plan view of the block being shaped or carved showing thearea upon which the spots of light are being projected.

Figure 6 is a vertical sectional view of the projector shown in Figure 5taken on line 6-5 of Figure 5.

Figure 7 is a sectional view on line 1-1 of Figure 6 showing the filmgate or aperture plate and a, portion of the film.

Figure 8 is a plan view showing a portion of a modified form of filmwith grid markings thereon, and

Figure 9 is a diagrammatic perspective view showing a partially carvedblock and the projection apparatus for projecting the photographsthereon so as to form the optical plastic image, and also showing theprojector of the present invention projecting a pattern of light uponthe block.

Referring to the drawings in detail, Figure 9 shows a preferred generalarrangement used in practicing the present invention. I5 and iii are twoprojectors, such as are shown in my Patent No. 1,980,981, or which maybe the projectors of a Multiplex apparatus. Two overlapping photographsof the terrain are placed in these projectors which are adjusted tobring the photographs into stereoscopic relationship so that an opticalplastic image I8 is produced which is located so as to appear to liebeneath the top surface of the block 20 of carvable material such asplaster of Paris. The plastic image may be rendered visible by theanaglyphic method. which comprises the projection of one of thephotographs through a blue screen and the other photograph through a.red screen, whereupon the plastic image may be observed by use of a pairof glasses with red and blue lenses. If preferred, the flicker methoddescribed in my patent aforesaid may be employed in which the twophotographs are alternately projected and viewed through a shutter whichpermits first one and then the other to be observed in rapid succession.This also produces a visible plastic image. The operator, observing theplastic image apparently below the surface of the block 20, thenproceeds with suitable tools to carve or otherwise shape the block toconform with the optical plastic image projected by the projectors l5and It. This operation is facilitated by providing means for renderingthe surface upon which the work is being done clearly visible andidentifiable so that it may be distinguished from the projected plasticimage.

The preferred means employed for this purpose comprises what may betermed a pattern projector 25 which throws a bright pattern of Figure 5is a plan view partly in section of light upon the surface of the block.The operathe projector shown in Figure 3.

tor is able to distinguish where this pattern falls .upon the surfacebeing carved and is thereby enabled to carve away the surface of theblock until such surface, identified by the pattern of light rays,coincides with the optical plastic image produced by the projection ofthe two photographs. In Figure 9 the pattern of light rays is indicatedby the grid marks 21, 28 and 28. The block is indicated as being partlycarved away, the marks '28 falling upon the original surface of theblock, the marks 28 falling upon a partially carved surface, and themarks 21 falling upon a surface of the block which has been fully carveduntil it coincides with the optical plastic image I8.

The pattern projector 25 may be of any suitable form, a simple formbeing shown for instance in Figure 1. As here shown a standard 35 ismounted on a movable base 88 which is supported upon a table 31. Alsosupported on the table is a block of carvable material 38 which isplaced under the projectors I5 and I6 (Fig. 9). Mounted on the standard85 is a source of light, such as an electric light bulb 48, the beamfrom which passes through a condenser 42 and then through a movableplate, film or disk 44, which is provided with numerous transparentportions or perforations 46. (Fig. 2.) The disc 44 is mounted on arotary shaft 48 driven by an electric motor 49 through suitablereduction gearin so that the disc 44 rotates at a slow speed. Preferablythe speed of the motor may be varied in any suitable manner as by arheostat indicated at 5|. The disc 44 is opaque, except for the numeroustransparent spots or perforations 48, sothat a slowly travelling patternof spots of light is projected by the projector. This pattern isprojected upon the block 38 and as the beam of spots is usuallyprojected at an angle it is desirable to provide an adjustable lens 53mounted on a standard 54, the lens being angularly adjusted to producethe focusing of the attern of spots upon the carved surface of theblock. The spots of light are preferably focused to be sharp at theaverage line of elevation of I the finished carving, such line beingindicated at 56. In this way approximate sharpness of projection will besecured at all times. The adjustment of the lens 53 to secure thisresult occurs when the central transverse plane through the lens,indicated at 58, intersects the plane 58 of the disc 44 on a line 0which lies in the average plane 58 of the carving.

The slow rotation of the disc 44 causes the pattern of spots to moveslowly over the block being carved, and thereby enables this pattern,where it falls upon the surface of the block, to be clearly visible anddistinguishable from the projected optical plastic image cast by theprojectors I5 and I6, as shown in Figure 9. This pattern enables thecarver at all times to identify the surface upon which he is working sothat he can tell when the surface is approaching coincidence with theoptical plastic image and when such coincidence is actually reached. Inthis way he is able readily to control his carving tools so as toproduce a model which accurately conforms to the projected plasticimage.

In Figures 3 to 7 a modified form of projector is shown in which theprojector proper comprises a casing lu-mounted between the arms of ayoke I2 and capable of tilting adjustment about a horizontal axis, suchadjustment being produced by turning the knurled discs I4 (Figure 5).The yoke 12 is pivotally mounted upon a rod 18 and may be loosenedthereon for adjustment about a vertical axis by means of a knurled nut11. The rod I6 is mounted for vertical adjustment in a standard I8 inwhich it may be held by a set screw 88.

In the casing 18 is a source of light, preferably an electric bulb 82having a concentrated filament, producing an approximately point sourceof light. The light is projected through a suitable condenser 84, passesout of the casing through a film gate or aperture plate 88 and through atelescopic tube 88 at the lower end of which is mounted a block 88 inwhich is adjustably mounted a lens holder 92 carrying a lens 83. Thelens holder and lens may be tilted by means of a knurled head 84. Theouter section of the telescope tube carrying the block 88 is preferablyprovided with adjusting means such as a rack 85 engaged by a pinion 86which may be rotated by means of a knurled head 98. The adjustment ofthe lens 88 by means of the heads 98 and 94 permits the beam ofpatterned rays to be brought into proper focus upon the block beingcarved, as already described. For producing the pattern of rays anendless strip of opaque film I88 is preferably employed, the film beingprovided with a suitable transparent pattern such as the perforationsshown at I8I in Figure '7. The film runs over a pair of idlers I 83 andI84 at the front end of the projector and over a driving sprocket I88which is arranged to be driven at slow speed through suitable reductiongearing by an electric motor I88, the speed of which may be controlledby a rheostat H8. The run of film extending between the idlers I83 andI84 is transverse to the axis of the projected beam and is locatedbetween the condenser and the aperture plate 86.

In some instancesinstead of using a film or light interrupting membercomprising a multiplicity of transparent spots or perforations, asindicated in Figures 2 and 7, the light interrupting member may beformed with a regular pattern preferably in the form of a grid ofcrossed transparent lines as indicated at H5 in Figure 8. Such a grid oflines produces a pattern which is very easily identified upon thesurface being carved and enables the form of such surface during thecarving to be readily identified. This pattern or grid of rays ispreferably caused to travel slowly across the surface being carved inthe manner already described.

An additional method which may be employed for enabling the pattern oflight to be identified and distinguished from the projected opticalplastic image, consists in varying the intensity of the light of theprojected pattern. Means for accomplishing this are indicated in Figure3 where a variable rheostat H8 is placed in the circuit of the lightbulb 82. This rheostat can be constantly varied as by means of anelectric motor I28 moving the rheostat core II9 through suitablereduction gearing so that a pattern of light is produced fluctuating orpulsating in in-' tensity. This enables the pattern to be readilydistinguished from the plastic image projected by the projectors I5 andI6. With this pulsation of the light intensity it may be possible todispense with the moving of the film or light interrupting member,although preferably both the moving film and the means for pulsating theintensity of light are employed.

By the use of the means for projecting spots or a pattern of rays uponthe surface to be carved, which spots or pattern can be distinguishedfrom the projected optical plastic image, it is possible to determine atall times the form of the surface being shaped or carved and to rapidlyform such surface into coincidence with the optical plastic image, so asto produce an accurate three dimensional replica of the optical plasticimage. The speed and accuracy of production of this replica is of theutmost importance particularly in the making of maps for militarypurposes.

While I have described in detail certain preferred procedures to befollowed in practicing my invention which I have found to be convenientand practicable, and while I have illustrated and described in detailcertain forms of apparatus which I have found well adapted to carryingout the required operation, I do not wish to be understood as limitingmyself to the performance of the process in the precise manner set forthor the following of a particular sequence of operations where notessential to secure the intended result, or to the use of the particularapparatus as set forth in the specification, as I realize that changesboth in procedure and in the apparatus are possible and I further intendeach step or sequence of steps and each element or instrumentalityapnearing in any of the following claims to be understood to refer toall equivalent steps, sequences of steps, elements or instrumentalitiesfor accomplishing substantially the same result in substantially thesame or equivalent manner.

I claim:

1. A method of producing a relief map which consists in projecting apair of overlapping aerial photographs upon a block of material in suchrelationship as to produce an optical plastic image of terrain on theblock, simultaneously projecting upon the block a pattern of light rayswhich can be distinguished from the optical plastic image and shapingthe surface of the block to coincide with the optical plastic image.

2. In a projector of the character described, a casing containing asource of light and means for projecting light from said source in aconcentrated beam, a support upon which said casing is mounted forangular adjustment, a telescopic lens support carrying a lens mounted inthe axis of said beam, means for angularly adjusting said lens about anaxis transverse to the axis of the beam, an endless opaque film movablymounted in said casing and having a run extending transversely of theaxis of said beam, said film having small light transmitting areas, andmeans for driving said film.

3. In a projector of the character described a casing containing asource of light and means for projecting light from said source in aconcentrated beam, a support upon which said casing is mounted forangular adjustment, a telescopic lens support carrying a lens mounted inthe axis of said beam, means for angularly adjusting said lens about anaxis transverse to the axis of the beam, an endless opaque film movablymounted centrated beam, a support upon which said casing is mounted forangular adjustment, a telescopic lens support carrying a lens mounted inthe axis of said beam, means foriangularly adjusting said lens about anaxis transverse to the axis of the beam, an endless opaque film movablymounted in said casing and having a run extending transversely of theaxis of said beam, said film having light transmitting lines thereonforming a grid, and means for driving said film.

5. A method of producing a relief map which consists in projecting apair of overlap ing aerial photographs on a block of material in suchrelationship as to produce an optical plastic image of terrain on theblock, shaping the surface of the.

block to coincide with the optical plastic image, and producing on thepartially shaped surface of the block a visible pattern distinguishablefrom the optical plastic image so as to enable the surface being workedon to be distinguished from the image being reproduced.

6. A method of producing a relief map which consists in projecting apair of overlapping aerial photographs upon a block of material in suchrelationship as to produce an optical plastic image of terrain upon theblock, shaping the surface of the block to coincide with the opticalplastic image, and rendering portions of the surface being shapedluminous in a manner to distinguish from the optical plastic image beingreproduced.

7. A method of producing a relief map which consists in projecting apair of overlapping aerial photographs on a block of material in suchrela-- tionship as to produce an optical plastic image of terrain uponthe block, shaping the surface of the block to coincide with the opticalplastic image, projecting upon the partially shaped surface of the blockas the shaping proceeds a pattern of light rays which can bedistinguished from the optical plastic image, and causing said patternof rays to shift on said surface.

8. A method of producing a relief map which consists in projecting apair of overlapping aerial photographs upon a block of material in suchrelationship as to produce an optical plastic image of terrain on theblock, shaping the surface of the block to coincide with the opticalplastic image, projecting upon the partially shaped surface of the blockas the shaping proceeds a pattern of light rays which can bedistinguished from the optical plastic image, and varying the intensityof said pattern of rays.

9. A method of producing a relief model of a three dimensional objectwhich consists in simultaneously projecting a pair of overlappingphotographs of the object taken from different camera positions on ablock of material in such relationship as to produce an opticalstereoscopic plastic image of the object on the block having theappearance of the object in three dimensional relief, shaping thesurface of the block to coincide with the three dimensional opticalplastic image and projecting upon the partially shaped surface of theblock as the shaping proceeds a pattern of light rays which can bedistinguished from the optical plastic image so as to enable thesurfacebeing worked on to be distinguished from the image that is beingreproduced.

10. A projector for use in shaping objects to correspond with an imageprojected thereon from another source of projection, said projectorcomprisinga light source arranged to project a beam at the object to beshaped and a screen interposed in said beam, said screen having smalllight transmitting areas so as to transmit an interrupted pattern ofrays, and automatic means independent of the screen for constantlyvarying the intensity of the projected beam so as to cause the patternof rays to pulsate in intensity;

11. A method of producing a relief map which consists in projecting apair of stereoscopically related representations of the terrain to bemapped upon a block oi material in such relation as to produce anoptical stereoscopic plastic image of the terrain showing the terrain inthree dimensional relief, shaping the surface of the block to coincidewith such three dimensional optical plastic image, and projecting uponthe partially shaped surface of the block as the shaping proceeds apattern 01' light rays which can be distinguished from the opticalplastic image so as to enable the surface being worked on to bedistinguished from the image that is being reproduced.

HEREWARD LESTER COOKE.

